Simple interest is a method of calculating interest where the interest amount is computed only on the original principal amount. Unlike compound interest, simple interest does not take into account accumulated interest from previous periods.
Simple interest is commonly used for short-term loans, car loans, personal loans, and some savings accounts. It's straightforward to calculate and easy to understand.
Follow these detailed steps:
Where: I = Interest, P = Principal amount, r = Annual interest rate (decimal), t = Time in years
Total Amount: A = P + I = P(1 + rt)
For months: I = P × r × (months/12)
For days: I = P × r × (days/365)
Problem: You borrow $5,000 at 8% simple interest for 3 years. How much interest will you pay?
Solution:
Simple interest is the most straightforward way to calculate interest - it's charged only on the original principal. This makes it ideal for short-term loans, car loans, and understanding basic interest concepts.
Finance Guide #6 - Simple Interest - Here are practical situations where you'll use this calculation:
Simple interest is calculated only on the principal amount. Compound interest is calculated on the principal plus any accumulated interest. Over time, compound interest results in higher returns for investments and higher costs for loans.
Simple interest is typically used for short-term loans (less than a year), car loans, some personal loans, and bonds. Most mortgages, savings accounts, and long-term investments use compound interest instead.
For simple interest calculations, divide the number of months by 12 to get years (6 months = 0.5 years). For days, divide by 365 (or 360 for some financial calculations). For example, 90 days = 90/365 ≈ 0.247 years.